HIGLEY and BOND: CHINOOK SALMON IN A RESERVOIR 



inclined-plane trap. Screens on the spillway 

 forced emigrating fish to enter the trap. After 

 spill had ceased, additional outflows of 0.071 

 m'/s [2.5 cfs (cubic feet per second)] were 

 produced by using a U-shaped iron tube as a 

 siphon. The time or amount of outflow was 

 otherwise uncontrolled. 



Many of the measurements were taken in 

 English units, and these occasionally are pre- 

 sented for clarity. 



DESCRIPTION OF RESERVOIR 



Happy Valley Reservoir (Figure 1) lies be- 

 hind an eaith-filled dam constructed on Quartz 

 Creek in the Warm Spring River watershed. 

 The stream flowed at rates up to 1.13 m^/s 

 (40 cfs) during the winters of the study. These 

 inflows replaced water used for summer irriga- 

 tion and produced spillway outflows of up to 

 0.56 m3/s (20 cfs). Summer inflows dropped to 

 less than 0.028 ms/s (1 cfs). 



At full pool, the reservoir covers 7.5 hectares 

 and has a maximum depth of 12.8 m (42 feet). 

 For most of the 1961 and 1962 summers these 

 dimensions were reduced to 6.1 hectares and 



10.7 m (35 feet) by irrigation drawdown. Mini- 

 mal dimensions were 4.9 hectares and 9.1 m 

 (30 feet), occurring from late summer to early 

 winter. 



The reservoir receives a heavy sediment load; 

 Secchi disc visibility was 10 cm after a 1961 

 rainstorm and did not exceed 2.1 m during the 

 study. The flat central plain region of the res- 

 ervoir is a mixture of this sediment and organic 

 deposits capable of releasing large gas bubbles. 



Air temperatures of -34°C and ice cover to 

 18-cm thick occurred under winter conditions; 

 summer temperatures exceeded 27°C at 0.8 m 

 (Figure 2). Thermal stratification was evident 

 from May to September. In July and August, 

 when temperatures were high and stratification 

 most severe, the upper 1.5 m was frequently 

 21° to 27°C, and only at depths of 2 m or more 

 could temperatures below 20°C be found. Figure 

 3 illustrates the seasonal patterns in tempera- 

 ture profiles. 



The concentration of dissolved oxygen was 

 greatly affected by thermal stratification and 

 by decomposition occurring in the organically 

 rich bottom of the reservoir. During July and 

 August, measurable amounts of dissolved oxy- 



^Ouart2 



HAPPY VALLEY RESERVOIR 



Wasco County, Oregon 



Township 7 South. Range 12 East. Section 16 

 Willamette Meridian 



Locafion ot 

 Reservoir 



WASCO 

 CO. 



Figure 1. — Contour map of Happy Valley Reservoir. The 42-foot depth was sampling station I, and 45 m directly off 



the spillway was sampling station 2. 



879 



